• Journal of Advanced Navigation Technology
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• v.21 no.1
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• pp.58-65
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• 2017

Global navigation satellite system (GNSS) has a weakness of signal integrity caused by broadcasting type data transmitting direct to user from navigation satellite. Loss of GNSS signal integrity can make a catastrophic event in the operation of unmanned aerial system (UAS) because position decision is only depended on GNSS. So it is required to apply alternative method to reduce a risk and to guarantee a GNSS signal integrity for UAS operation. This paper addressed the reason of loosing GNSS signal integrity, the effectiveness of signal jamming/spoofing and GNSS application trend for UAS. Also suggested the flight safety enhancing method in case of GNSS signal jamming for UAS as technical and political approaches.

• Journal of Chest Surgery
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• v.37 no.4
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• pp.335-341
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• 2004

Traumatic cardiac injury is very rare but mortality is very high when the diagnosis and management are delayed. We reviewed our case retrospectively. Material and Method: From March 1995 to July 2003, 17 patients were diagnosed as having traumatic cardiac rupture. Five patients were stabbed, seven patients were motor vehicle accidents, four patients had fallen down, and the cause was unknown in one patient. Emergency operations were done and six patients were operated under CPB. Result: Four patients died during or after operation. The mean ICU stay period was 3.86$\pm$3.35 days and the mean hospital stay was 18.27$\pm$14.99 days. No mortality was observed in those whose vital signs were stable in the operating room. Conclusion: Preoperative vital status was very important and thoracic traumatic patient should be suspected as having cardiac injury.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5D
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• pp.705-717
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• 2011

The number of horizontal tower cranes, major hoisting machineries for lifting approximately 50% of entire materials in construction projects, is rapidly increasing, but a number of accidents related to the tower cranes are being continuously occurred in construction sites as well. In particular, telescoping works in the horizontal tower cranes have showed the greatest safety concerns such as falls and collapses. It is due to the fact that tasks inserting a new mast in the space made after raising telescoping cage by fluid pressure and ascending it to the required height in the telescoping works include a series of dangerous factors in safety aspects, and might cause very serious and unexpected accidents in construction sites. The primary objective of this research is to propose two conceptual models for automating the telescoping work in horizontal tower crane and conduct their technical feasibility analyses. In this study, a design concept, a position control system using hydraulic cylinders is suggested as a better alternative for automating the telescoping work. Its potential safety improvement rate compared to the conventional method is also analyzed and presented in this study.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.2
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• pp.304-310
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• 2010

Chronic pain and herniated disk is a common disease that 80% of adults are experienced. There diseases rates of caused by the physical shock, such as the traffic accident, and the accidental fall is about 10%. And the most of these diseases is caused by having habitual incorrect position. People know that incorrect position would cause to accumulate continuous stress, but it is not easy to correct position. Because it does not recognize incorrect position repeated habitual consequently. This system collects data of user position after sensors that could measure position attach on use and presumes correct position used by position presumption algorithms. Its system purpose is continuing incorrect position could be aware to user and lead to change to correct position to prevent habituation of incorrect position. If habitual of correct position continues through accurate measurement and repeating cognitive learning, it would help for children and chronic patience.

• Advances in pediatric surgery
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• v.11 no.2
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• pp.115-122
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• 2005

Falls from a height are the leading cause of injury and death among urban children. This study describes the incidence, clinical characteristics, and treatment results of children under 15 year of age who fell from a height of more than one meter and were admitted for abdominal injury. The medical records of 585 consecutive patients treated between January 1997 and December 2003 at Ewha Womans University Mokdong Hospital were analyzed retrospectively. The falling heights were 1 to 31.2 meters, and 28 patients(4.8 %) suffered from blunt abdominal trauma. The male to female ratio was 2.1: 1. The median age of the victims was 5.5 years, and the median height fallen was 3 meters. Fifteen patients (53.6 %) were injured during the summer and seventy-nine percent of the falls occurred between noon and 9 pm. Eighteen (64.3 %) of falls occurred in residential place and 19(67.8 %) of patients arrived at the emergency department within 30 minutes of the accident. Only 16 patients (57.1 %) complained of abdominal pain. Liver injuries were found in 12(42.9 %), spleen injuries in 5(17.9 %), kidney injuries 3(10.7 %), pancreatic injuries in 1(3.6 %) and nonspecific abdominal injuries in 9(32.1 %) cases. Increased SGOT and SGPT were found in 23(82.2 %) and 18(64.3 %) cases. Eleven patients (39.3 %) had associated head injuries. Limb injuries were present in 17.9% and thoracic injuries in 7.1%. Twenty-five patients (89.3 %) recovered without operation. The median length of hospital stay was 6 days (2 -20 days). Despite the absence of abdominal symptoms or shock, falls from a height in children may carry significant intra-abdominal organ injuries. The height falling could not predict the degree of the abdominal injury. For the evaluation of potential abdominal injuries, CT scan should be utilized.

• The Korean Journal of Air & Space Law and Policy
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• v.21 no.2
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• pp.9-53
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• 2006

오늘날 항공기사고는 우리나라뿐만 아니라 세계도처에서 때때로 발생되고 있다. 특히 외국항공기의 돌연한 추락 또는 물건의 낙하로 인해 지상에 있는 제3자에게 손해를 입히는 경우가 간혹 발생되고 있다. 이와 같은 사건에 있어 가해자(항공기운항자)는 피해자(지상 제3자)에 대하여 불법행위책임을 부담하게 되는데 이 사건해결을 위하여 1952년 및 1978년의 개정로마조약 등이 있음으로 본 논문에서는 이들 조약의 성립경위 및 주요내용과 개정이유 등을 설명하였다. 현재 국제민간항공기관(ICAO)에서는 2001년도 미국의 9,11테러사건 이후 이와 같은 사건의 법적조치와 대응을 위하여 1952년 개정로마조약의 현대화에 관한 새로운 조약초안이 발표되었다. 본 논문에서는 이 새로운 조약초안의 현대화를 위한 ICAO의 활동과 이 조약 초안에 대한 주된 내용과 필자의 논평(견해)을 밝히었다. 한편 본 논문에서는 항공운송인의 책임에 관계된 국제조약과 세계 각국(미국, 영국, 독일, 프랑스, 러시아, 오스트레일리아, 중국 등)의 입법례 등을 참작한 후 우리나라의 현실에 적합한 항공운송법 시안에 관한 국내입법의 추진방향과 항공운송약관의 효력문제, 동법시안을 제정하여야만 되는 이유, 입법경위, 입법방안, "항공운송법 시안"의 주요항목 등 작성하여 제시하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.2
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• pp.31-39
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• 2012

Recently new construction and reconstruction of the bridge have been required to minimize traffic congestion, environmental disadvantage, to reduce the period of construction, and to improve the quality and workability during the construction. For this reason, the application of modular bridge system, which is assembly of the structural members, is necessary to prepare for near future. Fall of girders can occur at the moment to connect between precast girders during the construction, so appropriate cross beams should be installed to solve the mentioned problem. In this study, understanding the structural characteristics and domestic and international case of cross beam, alternative cross beam system for modular bridge was developed. To inspect the structural characteristics of the alternative system, specimens were built and static loading test was performed. Afterward, the behavior of cross beam interms of joints and load distribution was observed. Experimental results were analyzed and compared with each data. Therefore, the appropriate cross beam system for modular bridge will be chosen and proposed in this paper.

• Journal of Internet Computing and Services
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• v.23 no.3
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• pp.1-12
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• 2022

As the performance of Unmanned Aerial Vehicles (UAVs) are improving and the prices are lowering, it is expected that the use of UAVs will continuously grow in the future. It is important to always maintain control signal and video communication to operate remote UAVs stably, especially in military UAV operations, as unexpected jamming attacks can result in fatal UAV crashes. In this paper, to improve the network reliability and low latency when supporting UAV operations, the anti-jamming performance of Second generation Anti-jam Tactical UHF Radio for NATO (SATURN) networks is analyzed and enhanced by applying Forward Error Correction (FEC) and Minimum Shift Keying (MSK) modulation as well as Hamming code based multiple transmission techniques.

• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.45-52
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• 2022

In the field of UAM, which is attracting attention as a next-generation transportation system, technology developments for using UAVs have been actively conducted in recent years. Since UAVs adopted with these technologies are mainly operated in urban areas, it is imperative that accidents are prevented. However, it is not easy to predict the abnormal flight state of an UAV causing a crash, because of its strong non-linearity. In this paper, we propose a method for predicting a flight state of an UAV, based on a CNN-LSTM hybrid model. To predict flight state variables at a specific point in the future, the proposed model combines the CNN model extracting temporal and spatial features between flight data, with the LSTM model extracting a short and long-term temporal dependence of the extracted features. Simulation results show that the proposed method has better performance than the prediction methods, which are based on the existing artificial neural network model.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.217-225
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• 2024

Even after the introduction of Global Maritime Distress and Safety System (GMDSS), many maritime accidents occur. A method of transmitting a rescue signal when a person falls into the water from a ship is currently being researched and developed in various ways, but no products have been developed that use frequencies allocated for maritime mobile service. Accordingly, in this study, we designed and produced a man-over-board (MOB) device by applying Group B AMRD technologies, which were adopted through the latest revision of the International Telecommunication Union (ITU). In addition, a receiver and user interface were built to verify the performance of the transmitter, and we confirmed that it can be used in conjunction with existing electronic charts. This MOB device satisfies the general and technical requirements of Group B AMRD using AIS technology and uses integrated components for miniaturization for easy portability in a maritime environment. We expect that it will achieve excellent AIS communication and be essential in rapid response and safety in emergency scenarios.